One of the best things I have ever bought
Satechi iCel 5200 mAh I use it for all my charging needs Phone, Garmin and anything that uses USB cord. It's will charge my phone more than 3 times and will run my GPS for a few days.
Enough power and amps to drive device and charge at the same time, not just run your device from and external power source.
And they make
little speakers that sound great also if you ever wanted a portable speaker!